Kinetic and Equilibrium Study on the Adsorption of Methylene Blue From Aqueous Solution Onto Coffee Husk Activated Carbon

Abstract

In this study, the adsorption kinetics and equilibrium of methylene blue from aqueous solution onto activated carbon derived from coffee husk using one step ZnCl2 activation were investigated. The influence of initial methylene blue concentration and temperature were evaluated employing the batch experiment. To the experimental data, different kinetics and isotherm models were applied, finding that the best fitted is the pseudo-second-order equation and the Redlich-Peterson model, respectively. The mechanism of the adsorption was examined using the Weber and Morris model, and the obtained results suggested that the intra-particle diffusion was not the only rate-controlling step. The scale-up system was also designed for 50 - 90% methylene blue removal from an initial concentration of 100 mg L-1 at 30 oC.